This is serious.

[fjpod]

yikes

[drk]

first time I've seen an insult to opticianry and optometry in the same post.

Let's see to it that it's not the last. I like fun.

[Tigerclaw]

what?????? What part of the field do you work in?

My guess is "dating the optometrist".

[drk]

Bill, I'm with Tiger: unless you have a habit of running phorias through the phoroptor, eyeballing the phoroptor lens centration has never given me a problem in 25 years (until later today, now, of course...).

I just for fun earlier this week eyeballed it, read it, and compared it to a pupillometer reading and it was actually dead on. But I'm special that way.

[mervinek]

I just for fun earlier this week eyeballed it, read it, and compared it to a pupillometer reading and it was actually dead on. But I'm special that way.

Oh so, you didn't just pull it out of your butt?

[Barry Santini]

Bill, I'm with Tiger: unless you have a habit of running phorias through the phoroptor, eyeballing the phoroptor lens centration has never given me a problem in 25 years (until later today, now, of course...).

I just for fun earlier this week eyeballed it, read it, and compared it to a pupillometer reading and it was actually dead on. But I'm special that way.

Q: What about markedly dissimilar eye heights in stronger Rxs?

B

[Tigerclaw]

Q: What about markedly dissimilar eye heights in stronger Rxs?

Odds are my optician is better equipped to handle it.

[mervinek]

Odds are my optician is better equipped to handle it.

+1 Behind every good Optom is a great optician!

[Barry Santini]

Odds are my optician is better equipped to handle it.

I meant in a phoropter...

B

[Tigerclaw]

Phoropters don't move vertically aside from a small range of tilt. Also patients with significant vertical discrepancies tend to have head tilts. Eyeballing it is the most practical way to adjust for that 1 in 10,000 patient.

[Barry Santini]

Phoropters don't move vertically aside from a small range of tilt. Also patients with significant vertical discrepancies tend to have head tilts. Eyeballing it is the most practical way to adjust for that 1 in 10,000 patient.

Unnecessary prism, as well as the absence of necessary prism, has been encountered by me on a far more frequent basis than that

B

[Tigerclaw]

Not from me or drk.

[drk]

Unnecessary prism, as well as the absence of necessary prism, has been encountered by me on a far more frequent basis than that

B

I think what you're asking is how we eliminate lens-induced vertical prism when measuring a vertical phoria in a phoroptor. What is done is that the pinhole apertures are utilized; if the patient doesn't look through the optical center-aligned pinholes the necessary diplopia will vanish.

Good question.

[Dr. Bill Stacy]

Bill, I'm with Tiger: unless you have a habit of running phorias through the phoroptor, eyeballing the phoroptor lens centration has never given me a problem in 25 years (until later today, now, of course...).

I just for fun earlier this week eyeballed it, read it, and compared it to a pupillometer reading and it was actually dead on. But I'm special that way.

Yes, I habitually do distance and near phorias and fixation disparity testing in the phoropter, because those tests are so quick and easy, and yield such important information, just like pupillometry. I also do careful cover testing outside the refractor, and before prescribing any prism I check with loose prisms outside the refractor.

Glad you can eyeball it so close, or that the parallax faerie was on your side that day.

[Barry Santini]

I think what you're asking is how we eliminate lens-induced vertical prism when measuring a vertical phoria in a phoroptor. What is done is that the pinhole apertures are utilized; if the patient doesn't look through the optical center-aligned pinholes the necessary diplopia will vanish.

Good question.

Thank you!

B

[Dr. Bill Stacy]

I think what you're asking is how we eliminate lens-induced vertical prism when measuring a vertical phoria in a phoroptor. What is done is that the pinhole apertures are utilized; if the patient doesn't look through the optical center-aligned pinholes the necessary diplopia will vanish.

Good question.

I have to disagree with that. If there is no diplopia looking binocularly through pinholes and any diplopia vanishes, it's just as likely that the "pinhole pd" is so far off that one pinhole is actually outside the pupillary zone, which will also eliminate any diplopia. Also, relying on the subjective awareness of diplopia for such a crucial measurement is a pretty weak exercise, all to avoid using a mm rule for 5 seconds or a pupillometer for 7? Even if I have a trusted staff person do the pupillometry, I've already got a mm rule in my hand which I like to use for near cover testing (before refracting), and will often check the pd just to be sure. Mistakes do happen, objective measurements are always nice to have.

On Barry's comment, I find that most of the time any apparent vertical phoria can be reduced or eliminated by the patient raising or lowering their chin a bit, esp. in the case of any significant anisometropia in the 90 meridian.

[Tigerclaw]

And a PD measurement helps with vertical diplopia how, exactly?

[Dr. Bill Stacy]

And a PD measurement helps with vertical diplopia how, exactly?

Well if the vertical diplopia is due to a vertical strabismus, when you put the mm ruler up to the eyes and the pupillary reflexes are at different heights (as they will be), you can easily see the deviation by the tilt of the ruler out of the 180. It becomes way more and instantly obvious.

[drk]

Yes, I habitually do distance and near phorias and fixation disparity testing in the phoropter, because those tests are so quick and easy, and yield such important information, just like pupillometry. I also do careful cover testing outside the refractor, and before prescribing any prism I check with loose prisms outside the refractor.

Glad you can eyeball it so close, or that the parallax faerie was on your side that day.

I'm so much younger than you (ha ha) that I eschewed the routine phoroptor-based phoria/vergence testing, and only really do free-space with prism bars when indicated.

That's why we younger whippersnappers don't measure p.d. for an exam. I only do it if I need to calculate AC/A or demand, or get vertical phorias, or do other BV problem-solving stuff.

[drk]

I have to disagree with that. If there is no diplopia looking binocularly through pinholes and any diplopia vanishes, it's just as likely that the "pinhole pd" is so far off that one pinhole is actually outside the pupillary zone, which will also eliminate any diplopia. Also, relying on the subjective awareness of diplopia for such a crucial measurement is a pretty weak exercise, all to avoid using a mm rule for 5 seconds or a pupillometer for 7? Even if I have a trusted staff person do the pupillometry, I've already got a mm rule in my hand which I like to use for near cover testing (before refracting), and will often check the pd just to be sure. Mistakes do happen, objective measurements are always nice to have.

On Barry's comment, I find that most of the time any apparent vertical phoria can be reduced or eliminated by the patient raising or lowering their chin a bit, esp. in the case of any significant anisometropia in the 90 meridian.

You misunderstand my post.
1. measure pd
2. set phoroptor lens horizontal distance and use bubble level for trueness to horizon
3. pinholes introduced
4. vertical phoria measured with Risley prisms.
5. If patient loses diplopia, either they're suppressing or they've tilted their heads.

[Tigerclaw]

Well if the vertical diplopia is due to a vertical strabismus, when you put the mm ruler up to the eyes and the pupillary reflexes are at different heights (as they will be), you can easily see the deviation by the tilt of the ruler out of the 180. It becomes way more and instantly obvious.

I have an obnoxiously keen eye for detail, leads me to lots of uncomfortable discussions with patients like "Has your eyelid always drooped like that?"

[Dr. Bill Stacy]

You misunderstand my post.
1. measure pd
2. set phoroptor lens horizontal distance and use bubble level for trueness to horizon
3. pinholes introduced
4. vertical phoria measured with Risley prisms.
5. If patient loses diplopia, either they're suppressing or they've tilted their heads.

I sure did. But now I'm even more curious. Why the pinholes in the first place? As for #5, to me the most common loss of diplopia would be a difference in the vertical position of one eye from the other. Let's see, I'm not sure there is a medical term for that very common condition. Maybe we should coin one right here: maybe "Santini Asymmetry"?

[drk]

You mean hyperorbit or hypoorbit?

The point of the pinholes is to get the patient looking through the OCs of the refractive-error correcting lenses in the phoroptor. (If there are no sphere lenses in place, the person doesn't need the pinholes, of course.)

That's why I bother to take p.d.s and check vertical phorias in the phoroptor in the first place, vs. free space maddox rod with glasses on: with free-space if the glasses are high-powered and the frame is tilted (or the head is tilted), then there's spectacle-induced "pseudo" vertical phoria. It's factored out with a perfectly level pinhole aperture, OU, because they won't see double if they go off-level.

(I won't even begin to talk about ensuring "primary gaze", and habitual head tilts and all that jazz.)

[Dr. Bill Stacy]

You mean hyperorbit or hypoorbit?

The point of the pinholes is to get the patient looking through the OCs of the refractive-error correcting lenses in the phoroptor. (If there are no sphere lenses in place, the person doesn't need the pinholes, of course.)

That's why I bother to take p.d.s and check vertical phorias in the phoroptor in the first place, vs. free space maddox rod with glasses on: with free-space if the glasses are high-powered and the frame is tilted (or the head is tilted), then there's spectacle-induced "pseudo" vertical phoria. It's factored out with a perfectly level pinhole aperture, OU, because they won't see double if they go off-level.

(I won't even begin to talk about ensuring "primary gaze", and habitual head tilts and all that jazz.)

OK then, that's what I will call it, although Barry might be disappointed. I wonder if the WHO will assign it an ICD 10 code?

I had never heard of pinhole phorometry and having been taught by Darryl Carter, Ph.D. all about fixation disparity, I do not test far phorias in the refractor except in cases of manifest diplopia. Instead, I just use vectographic fixation disparity testing with no pinholes and best refraction lenses in place; very quick and easy and I think a lot more helpful in prescribing/not prescribing prism than phorometry. I still use phorias at NEAR in the phoropter, using the maddox rod and modified Thorington test card from UCB (also very quick and easy).

[fjpod]

What's all this got to do with the FTC rules....or is it just a p*****g contest over who is more neurotic in their testing.